How to streamline the casting pre-production process with your foundry
Do you want to avoid pre-production delays with your iron castings? It will save you countless hours, added cost and frustration.
That’s the message of Jesse Milks, President of State Line Foundries. “Often, between the time that we first quote a job until we start working on it, the PPAP requirements may change significantly. That requires a lot of communication about the customer’s requirements and qualifications and what will work best for them and the foundry,” he explains.
Get your foundry involved earlier in your product requirement and qualification development processes. A case in point is X-ray inspections of castings. Many quotes require it, but it’s not always the best way to verify the internal soundness of a casting instead of an X-ray, the foundry can section cut castings to check for internal porosity. The value of the casting being destroyed versus the cost of an X-ray inspection should be considered as well as the timing for both options.
Lastly, foundry engineers typically prefer reviewing section-cut pieces of an actual casting whenever possible. This allows them to understand the severity and exact location of any internal defects.
Another common example is dimensional checks. These can be performed in several ways, including calipers and rulers, CMM machines and 3D scans. The best approach depends on the geometry of the casting. When a customer requires a specific method of dimensional verification, it limits the foundry’s ability to use the most efficient method to conduct this test.
A third example highlights what can happen when a production part becomes a service part. State Line frequently receives tools that were once used by a production foundry to produce a large number of castings for new models of off-highway equipment. Now that the model is no longer in production, the OEM still needs to support the machines in the field with replacement parts.
Only a few dozen castings per year may be needed to fulfill these service requirements. But the PPAP may still require a multi-tiered set of sampling and testing procedures for the castings to be fully qualified. This process may have been well-suited to large production quantities but doesn’t make sense when State Line is only producing a handful of them per year.
“A more cost-effective approach is to have us check the first few castings, make sure the pattern tool is still dimensionally good, make sure the composition of the iron is meeting your needs, and then also ensure that the castings meet your machining and assembly needs,” Milks recommends. “If everything works out for those first few pieces, most likely the production run is going to be fine. Why? Because production foundry already worked out a lot of the bugs when it produced that part in larger quantities.”
No matter how many physical, dimensional and chemical tests an OEM’s qualifications require, Milks emphasizes that there’s no substitute for machining the castings. “Even if all of the tests indicate that it’s a good casting, machining it may uncover problem areas that weren’t evident before,” he adds.
This is especially important for older patterns that get transferred to State Line. “Often, a lot of the tribal knowledge that the previous foundry had accumulated, the tips and tricks they used to produce it in their casting infrastructure, gets lost when the tool gets transferred,” he cautions. “So it helps to take a few extra steps to make sure the castings truly meet the customer’s needs.”
A final challenge has to do with the typical quoting process. “When we first get asked to quote a part, we’re talking to an engineer or procurement person. They have one set of requirements, which they share in their RFQ. What’s missing are the qualifications that their quality people require. About 80 percent of the time, when we first get a request for quotation, we don’t know the qualification needs,” Milks emphasizes.
The foundry must collect information about the customer’s sampling and PPAP requirements and then re-quote the project. Working out those details, producing a revised purchase order and getting it approved can often delay projects for several weeks.
“Ideally we’d prefer to have a clear and concise list of qualifications up front. But if that’s not possible, then the OEM should be reasonable and flexible as we work through these requirements together, to come up with something that works well for both parties. That makes the whole process go more smoothly and can help to reduce lead times on their castings,” he counsels.
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